Semiconductor integrated circuits (ICs) are typically mounted in or on a printed circuit board (PCB) as part of a packaging process for making an electrical assembly. For electrical ICs, individual metal electrical conductors are typically used to make the electrical connections between first metal pads on the IC and second metal pads on the PCB.
The need for high-bandwidth communication with electrical ICs has prompted the addition of optical waveguide connections between optical+electrical ICs (“OE-ICs”) and OE-PCBs that have both optical and electrical functionality and optical and electrical connection locations. Like the electrical connections made for electrical ICs, optical and electrical connections are made between OE-ICs and OE-PCBs to form a photonic assembly.
The challenges in fabricating photonic assemblies include defining the optical waveguides and then establishing the optical interconnections between the OE-IC and the OE-PCB. Since optical waveguide technology has been used extensively in telecommunications, it would be desirable to use optical waveguides such as optical fibers as the waveguides of the OE-PCB. However, the bending requirements for the optical waveguides, along with the large number of optical interconnections needed and the alignment issues associated with making optical waveguide interconnections, have made the use of optical waveguides OE-PCBs problematic.